Nuclear Power Applications

Materials for nuclear power plants include Zircaloy alloys for reactors and reactor vessels, various materials for steam generators, turbines, heat exchangers, turbines, and piping, plus Boron enriched stainless steel materials for radiation shielding, and B4C pellets for B10 concentration, and materials must retain their function, strength and toughness under bombardment by neutrons and gamma radiation.

For example, steels in nuclear power plants can be damaged when high-energy neutrons displace metal atoms from their normal position in the microstructure, leaving defects in the steel. In other cases, the atoms themselves can absorb neutrons. This can result in the creation of helium or hydrogen within the microstructure, causing the irradiated component to swell, and reducing its resistance to fracture.

However, development and testing of advanced steels have shown that, for example, manganese-molybdenum-nickel ferritic steels can resist such damage in applications such as pressure vessels. These steels must be quenched and tempered to produce a defined microstructure.

Iron-based amorphous metal formulations with chromium, molybdenum, and tungsten have shown that they can provide the corrosion resistance believed to be necessary for such applications. Rare earth additions enable very low critical cooling rates to be achieved. The boron content of these materials, and their stability at high neutron doses, enable them to serve as high efficiency neutron absorbers for criticality control. Ceramic coatings may provide even greater corrosion resistance for container applications.

One of NSL’s most important responsibilities is to evaluate nuclear plant materials such as stainless steels, superalloys, and alloys of titanium, nickel, zirconium, and tungsten. Our experienced staff, advanced analysis instrumentations, and metallographic analysis capabilities can assure operators of nuclear power plants that their materials of construction will function as designed and that commercially available material can meet the requirements to be used at a nuclear site. Besides safety related items, we also analyze commercially dedicated items such as mechanical lubricants, polymeric materials, computer keyboards, ball point pens, rubber gloves, etc. specifically used in nuclear facilities to insure that they meet the testing requirements.